Chennai (PTI): The alliance between the PMK and the DMK, leading the ruling DPA in Tamil Nadu, has run into rough weather with PMK founder S Ramadoss issuing an ultimatum to Chief Minister M Karunanidhi to concede his party's demand for a Rajya Sabha seat by March 15.

DMK chief Karunanidhi had on Wednesday rejected the PMK's demand for the seat, by allocating two seats to his party and the Congress and one to the CPI(M).

Six Rajya Sabha seats are falling vacant in the state, to which elections are due on March 26. The sixth seat will go to the Opposition led by AIADKM Chief J Jayalalithaa.

Ramadoss said here after an urgent meeting of the party executive committee that his party felt "humiliated" by the "unilateral" announcement by Karunanidhi on the seat allocation.

"The DMK chief has committed an injustice to the PMK which has been with him right from 1996. But, we are being continuously ignored by the DMK. They want us to leave the alliance. But, we are firm that our alliance with the Congress at the Centre should continue. The ball is in the DMK's court," he told PTI after the meeting.

The committee authorised Ramadoss to take an appropriate decision that would "assert the party's rights and protect its self-respect."

The PMK founder said the party functionaries had put forth three views -- one to field its own candidate, boycott the polls or to hold talks again with the DMK.

Since there was time till March 15 (last date for filing nominations), the party would hold talks with the DMK leadership, he said, but was quick to add that he would not meet Karunanidhi in this regard.

Ramadoss said the DMK chief's argument that the PMK was already allotted a Rajya Sabha seat in 2004 and it would be given chance again only in 2010 when that seat's term ends, did not hold water now as that agreement was meant only for the 2004 Lok Sabha polls.

"We were hurt by his remarks which implied that we're entitled only for a single RS seat. His appeal for our support to his nominees only added insult to injury."

"We've no objection to allocation of two seats to the Congress and one to the CPI(M). But, let the DMK part with one of its two seats as it is enjoying power in the state," he said.

As the leader of the alliance, it was Karunanidhi's responsibility to prove that the PMK was not being ignored and to ensure that the "injustice" rendered to the party was removed, he said.

Asked whether his party would seek the Opposition AIADMK's support in case a decision was taken to field a candidate, Ramadoss said "the question does not arise."

Asked why he was hesitating to snap ties with the DMK despite the "insults," the PMK founder said "in politics, we cannot take hasty decisions."